This invention relates to reading devices to enable people with low vision to read books, magazines, newspapers, etc. More specifically, this invention relates to a hand held camera which may be passed over text to display the text in greatly magnified form on a screen, such as a television screen.
Low vision is defined as a condition where ordinary eye glasses or contact lenses cannot provide sharp sight. Presently, the number of people having low vision is estimated to be over 14 million people in the United States alone. Low vision can be caused by a variety of eye problems. Macular degeneration, glaucoma, diabetic retinopothy, detached retina, and retinitis pigmentosa are but a few of the conditions which can cause low vision. Individuals with low vision find it difficult, if not impossible, to read newspapers, books, recipes, prescriptions, or other reading material. Reading glasses and magnifying glasses provide insufficient enlargement for large numbers of people.
One generally well known method of providing greater magnification is the use of closed circuit television systems which include a video camera, a monitor for displaying the image, and a means for transferring the image from the camera to the monitor. These systems fall generally into two categories. The first category includes desk-top systems which have a video monitor with a camera mounted beneath it. A support arm holds the monitor, camera, and control box above a movable support platen for holding the material to be viewed. Examples of desk-top systems are shown in U.S. Pat. Nos. 3,819,855 to Rush et al., U.S. Pat. No. 3,816,646 to Cinque, U.S. Pat. No. 4,115,813 to Mikami, and U.S. Pat. No. 4,928,170 to Soloveychik et al. These systems are large, and thus not easily transportable.
The second category of devices includes a variety of hand held systems. These systems consist of a video monitor connected to a small camera housed in an enclosure which can be moved about the printed material by hand. Such hand held devices are shown in U.S. Pat. No. 3,993,865 to Browne et al, U.S. Pat. No. 4,136,361 to Doan, and U.S. Pat. No. 5,046,163 to Priest et al.
All of these prior devices have sever limitations. They are often difficult to use, lack portability, and restrict the user to a specific position in front of the unit in order to work the controls. Earlier attempts at hand held systems have major draw-backs. When their camera lens is placed close to the object (one-half to two inches away) sever barreling, or fish-eye distortion and astigmatism distortion become quite evident. Moreover variable magnification in hand held units has been provided by changing the distance of the camera from the printed matter. Some units provide exchangeable length legs or attaching the camera to a vertically movable stand. Changing leg extensions sizes is clumsy and frustrating for someone partially sighted and moveable stands are so large they are no longer a truly hand held device.
There exists therefore, a significant need for a truly portable full function hand-held video system that provides a substantially distortion free image with a variable magnification feature that automatically stays in focus and is easy to use.